Theory. Jazz Chords2

 Here they are: the 7 key chords of jazz harmony.  The post of 9 March provides an introduction.  


But as a reminder, a 7 chord is built by stacking three 3rds on topic of one another so that the total distance between the tonic and the upper most note form the interval of a 7th.  Thirds can be made up of either 3 or 4 semitones, and a 7 chord consists of either 10 or 11 semitones.


Major 7th
   Formula = 1, 3, 5, 7
  Semi-tones = 4 - 3 - 4
  Example
     Cmaj7 = C, E, G, B
Minor/Major 7th
   Formula = 1, 3b, 5, 7
  Semi-tones = 3 - 4 - 4
  Example
    C-M7 = C, Eb, G, B
Minor 7th
  Scale degree = 1, 3b, 3, 7b
  Semi-tones = 3 - 4 - 3
  Example
    Cmin7 = C, Eb, G, Bb
Half diminished 7th

  Scale degree = 1, b3, b5 b7
  Semi-tones = 3 - 4 - 3 

  Example: 

    Cm7b5 = C, Eb, Gb, Bb

Diminished 7th

  Formula = 1, 3b, 5b, 7bb
  Semi-tones = 3 - 3 - 3
  (aka, 2 tritones; the devils interval)
  Example: 
    C dim7 = C, Eb, Gb, Bbb (A)
Dominant 7th

  Formula = 1, 3, 5, 7b
  Semi-tones = 4 - 3 - 3
  Example
    C7 = C, E, G, Bb
Suspended (aka suspended dominant)

  Formula = 1, 4, 5, b7

  Steps = 5 - 2 - 3 

  Example:

    Cm7b5 = C, Eb, Gb, Bb